The present invention relates generally to solar heat collectors. More specifically this invention relates to a focusing solar heat collector.
Due to ever increasing usage of non-renewable energy sources such as fossil fuels, much attention is being directed toward solar energy. Solar energy has been found to be effective in providing space and water heating.
Many solar heat collectors are attractive in performance but lack in cost-effectiveness. Many solar heating systems require several years of operation to return the initial investment, turning many citizens away from solar energy as an alternative energy source. Therefore, there is a need for a simple, efficient, and most importantly, an inexpensive solar heat collector.
Solar heat collectors are generally divided into two catagories depending on how they function to utilize the sunlight.
One category of solar heat collectors utilizes the device of the "green-house effect". Usually they operate in a stationary position, taking advantage of light-transmitting covers which trap heat energy of longer wavelengths produced by penetrating shorter wavelengths of light which are absorbed by black surfaces situated beneath the covers. In U.S. Pat. No. 3,194,228 to Bargues, a black corrugated panel with conduits attached is used to absorb solar radiation. Water is circulated through the conduits to collect the heat. Another "green-house effect" type of collector is described in U.S. Pat. No. 4,055,163 to Costello et al. This collector differs from the Bargues collector in that a black liquid is utilized in lieu of a black corrugated panel to absorb solar radiation. This collector employs a non-focusing reflective surface to remove unwanted heat. The black fluid is circulated through a light-transmitting conduit which is situated above the reflective surface substantially masking the reflective surface from sunlight when in operation. The heated black liquid is circulated through a heat exchanger which transfers heat to water.
Related to the present invention are focusing type solar heat collectors. Focusing type solar heat collectors, which represent the second category of solar heat collectors, obtain high efficiency by concentrating sunlight by means of reflectors or lenses. A large area of sunlight is focused onto a smaller target or conduit. A liquid such as water is circulated through the target or conduit to collect heat by conduction. In U.S. Pat. No. 2,907,318 to Awot, a corrugated reflected surface is employed as means for focusing sunlight onto conduits positioned in the valleys of the corrugations. This collector employs a light-transmitting cover air spaced over the conduits.